Method and apparatus for making an aerofoil-shaped blade



Nov. 26, 1968 METHOD AND Filed June 13, 1966 G. o. ECCLES ETAL 3,412,611

APPARATUS FOR MAKING AN AEROFOIL-SHAIED BLADE 2 Sheets-Sheet 1 Inventors WW 3% y W, M 2 MW A ttorng y;

Nov. 26, 1968 G. o. ECCLES 3,412,611

METHOD AND APPARATUS FOR MAKING AN AEROFOIL-SHAPED BLADE Filed June 13,. 1966 2 Sheets-Sheet 2 I I nventort (a d. W i. 4

m I W MW,MI Home United States Patent T 3,412,611 METHOD AND APPARATUS FOR MAKING AN AEROFOIL-SHAPED BLADE George Oswald Eccles, Skipton, and Joseph William Whitaker, Keighley, England, assignors to Rolls Royce Limited, Derby, England, a British company Filed June 13, 1966, Ser. No. 557,270 Claims priority, application Great Britain, July 22, 1965, 31,347 65 8 Claims. (Cl. 72-377) ABSTRACT OF THE DISCLOSURE A method of making a clapper blade comprising producing a blade having its blade portion finished forged and its clapper portion roughly forged and thereafter finish forging the clapper portion without effecting further forging of the blade portion. This is effected by an apparatus comprising a split clamp, and a split die which is disposed in the clamp and capable of limited sliding movement in longitudinal and transverse directions of the blade. Limited sliding movement of the die parts effects the finish forging of the clapper portions.

This invention concerns a method and apparatus for making an aerofoil-shaped blade (e.g. a rotor blade of a gas turbine engine compressor or turbine) which is provided, integrally with its blade portion, with a clapper portion, i.e. a portion disposed between the root and the tip of the blade by means of which the blade may be secured to an adjacent blade or blades of the same stage. Such blades may, for example, be of high aspect ratio, the clapper portions interconnecting the blades so as to reduce their flexibility.

In the case of such blades, the twist of the blade portion and the presence of re-entrant angles between the blade and clapper portions prevents finish forging of the whole blade in one single forging operation. Accordingly these blades have, in the past, been only partially forged and have required considerable machining.

According therefore to the present invention, there is provided a method of making an aerofoil-shaped blade having a blade portion and an integral clapper portion, said method comprising producing a said blade having its blade portion finished forged and its clapper portion roughly forged and thereafter employing a split die having parts which are movable both longitudinally and transversely of the blade portion to effect finish forging of the clapper portion without effecting further forging of the blade portion.

The blade portion is preferably finish forged at the same time as the clapper portion is roughly forged.

The blade having the said finish forged blade portion and roughly forged clapper portion may be placed in a split clamp within which the said parts of the split die are capable of limited sliding movement both longitudinally and transversely of the blade portion.

The clapper portion preferably comprises two clappers which are respectively disposed on diametrically opposite sides of the blade portion.

The blade may be initially formed by producing an extruded length of metal which may be ultimately formed into the blade and clapper portions, then forging said extruded length so as to produce diametrically oppositely disposed stubs thereon which may be ultimately formed into clappers and thereafter forging the blade so produced in a split die in which the blade portion is finish forged and in which the stubs are simultaneously roughly forged into clappers. Thus the stubs may be formed by heating a portion only of the said extruded length, subjecting the extruded length while so heated to Patented Nov. 26, 1968 a longitudinally directed impact whereby substantially to increase the diameter of the extruded length at the said portion, and then forging the said portion to form the said stubs.

The invention also comprises apparatus for carrying out the said method and comprising a split clamp provided with means for receiving and locating the blade having the said finish forged blade portion and roughly forged clapper portion, a split die which is adapted to be disposed in said clamp and parts of which are capable of limited sliding movement in the clamp both longitudinally and transversely of the blade portion when the blade is located in the clamp, and means for effecting the said limited sliding movement of the said die parts whereby to effect finish forging of the clapper portion without effecting further forging of the blade portion.

The said parts of the die may be arrangeable in the clamp so that they will be disposed on one side only of the clapper portion, there also beingprovided a replaceable split die which is arrangeable in the clamp so as to be disposed on the opposite side of the clapper portion.

The invention also comprises an aerofoil-shaped blade (e.g. a rotor "blade of a compressor of a gas turbine engine) when made by the said method or apparatus.

The invention is illustrated, merely by way of example, in the accompanying drawings, in which:

FIGURES 16 respectively diagrammatically illustrate various stages in the manufacture, in accordance with the present invention, of a rotor blade of a gas turbine engine compressor,

FIGURE 7 is a view looking in the direction of the arrow 7 of FIGURE 6,

FIGURE 8 is a diagrammatic, part-sectional, view of apparatus which may be used in the manufacture of the said blade, and

FIGURE 9 is a section taken on the line 99 of FIG- URE 8.

Referring to the drawings, a rotor blade 10 (see FIG- URE 6) of a gas turbine engine compressor (not shown) has a blade portion 11 and clappers 12, 13 which are integral with the blade portion 12, 13 and which are respectively disposed on diametrically opposite sides of the blade portion 11. The clapper 12 of one blade may be brazed or welded to the clapper 13 of the adjacent blade (not shown) of the same stage.

The blade 10 is made from a slug 14 (FIGURE 1) of any forgable metal. Thus the metal may, for example, be a titanium based alloy or may be a nickel based alloy sold under the Registered Trade Mark Nimonic.

The slug 14 is passed to an extrusion die (not shown) in which part of it is formed into an extruded length 15 (FIGURE 2) from which the blade portion 11 and clappers 12, 13 will ultimately be made, the remaining part 16 of the slug being that from which the root portion of the blade will ultimately be made.

A portion 20 (FIGURE 3) of the extruded length 15, which portion 20 is spaced from the tip 21 of the extruded length 15, is heated, and the tip 21 is then given a longitudinally directed impact which causes an increase in the diameter of the extruded length 15 at the portion 20.

The portion 20 is then forged, on diametrically opposite sides of the extruded length 15, to produce stubs 22, 23 (FIGURE 4) which may be ultimately formed into the clappers 12, 13 respectively.

The blade 10 is then passed to a two-part forging die (not shown) in which, as indicated in FIGURE 5, there will be simultaneously produced a finish forged blade portion 11, having a conventional twisted aerofoil shape, and roughly forged clappers 12, 13. The blade 10 will, moreover, in the course of this forging operation, be provided with locating portions 24, 25 at the tip and root of the blade and with a root portion 26 which will require some subsequent machining. The flash (not shown) produced at this stage is then removed and the blade 10 is then passed to the apparatus shown in FIGURES 8 and 9.

This apparatus comprises a split clamp having two parts 30, 31 which are provided with recesses 32 to receive snugly the root portion 26, recesses 33, to receive snugly part of the blade portion 11, and recesses 34 to receive snugly the locating portion 25.

Slidably mounted in the split clamp 30*, 31 are parts 35, 36 of a split die. The parts 35, 36 are provided with recesses 37 to receive snugly part of the blade portion 11 and with recesses 38 to receive snugly the locating portion 24.

The die parts 35, 36 are adapted to be arranged on one side of the clappers 12, 13, there being provided a replaceable two-part split die 40, 41 whose parts are arrangeable in the clamp 30, 31 on the other side of the clappers 12, 13. The die parts 40, 41 are not, in operation, movable with respect to the clamp 30, 31, but they may be replaced by other such die parts if it is desired to alter the shape of the clappers 12, 13.

The die parts 35, 36 are spaced from the die parts 40, 41 by a gap 42 (e.g. of 0.08" to 0.1) in which the roughly forged olappers 12, 13 may be received, the gap 42 permitting the die parts 35, 36 to be given limited sliding movement by a ram 43 towards the die parts 40, 41 and longitudinally of the blade portion 11. Springs 44, acting between the clamp 30, 31 and die parts 35, 36, are provided to urge the die parts 35, 36 away from the die parts 40, 41, while the die parts 35, 36 are provided with guide slots (not shown) to receive guide members 45 carried by the clamp 30, 31.

The die parts 35, 36 are also spaced by small clearances (not shown) from the adjacent parts of the clamp 30, 31 to permit very limited sliding movement (e.g. of 0.002") of the die parts 35, 36 transversely of the blade portion 11.

When the blade of FIGURE 5 is placed in position in the apparatus of FIGURE 8 and the ram 43 is operated, the die parts 35, 36 will move longitudinally of the blade portion 11 and will be cammed apart by the shape of the blade portion 11 so as to move transversely of the latter. As a result, the clappers 12, 13 will be finish forged, while no further forging of the blade portion 11 will occur.

The clamp 30, 31 is provided with grooves 46 to receive the flash 47 (FIGURE 7) and such grooves (not shown) are also provided in the die parts 35, 36.

The blade 10 is then removed from the apparatus of FIGURES 8 and 9, the flash 47 is removed, the root portion 26 is machined to size, and the locating portions 24, 25 are removed.

We claim:

1. A method of making an aerofoil-shaped blade having a blade portion and an integral clapper portion, said method comprising producing a said blade having its blade portion finish forged and its clapper portion roughly forged, and thereafter finish forging the clapper portion without effecting further forging of the blade portion.

2. A method as claimed in claim 1 in which the blade portion is finish forged at the same time as the clapper portion is roughly forged.

3. A method as claimed in claim 1 in which the clapper portion comprises two clappers which are respectively disposed on diametrically opposite sides of the blade portion.

4. A method as claimed in claim 1 in which the blade is initially formed by producing an extruded length of metal which may be ultimately formed into the blade and clapper portions, then forging said extruded length so as to produce diametrically oppositely disposed stubs thereon which may be ultimately formed into clappers, and thereafter finish forging the blade portion and simultaneously roughly forging the stubs into clappers.

5. A method as claimed in claim 4 in which the stubs are formed by heating a portion only of the said extruded length, subjecting the extruded length while so heated to a longitudinally directed impact whereby substantially to increase the diameter of the extruded length at the said portion, and then forging the said portion to form the said stubs.

6. An apparatus for finishing a roughly forged clapper portion of an aerofoil-shaped blade already having a finished forged blade portion, the apparatus comprising: a split clamp having means for receiving and locating the aerofoil-shaped blade therein; a split die disposed in said clamp, said split die having parts capable of limited sliding movement in said clamp both longitudinally and transversely of the blade portion when the aerofoil-shaped blade is located in said clamp; and means for effecting the limited sliding movement of the parts of said die to thereby finish forge the clapper portion without effecting further forging of the blade portion of the aerofoilshaped blade.

7. Apparatus as claimed in claim 6 in which said movable parts of said die are disposed on one side only of the clapper portion; and including a replaceable split die arranged in said clamp and disposed on the opposite side of the clapper portion.

8. Apparatus as claimed in claim 6 in which the clamp and die parts are provided with grooves to receive any flash of the clapper portion.

References Cited UNITED STATES PATENTS 2,743,509 5/ 1956 Friedman 29l56.8 2,999,303 9/1961 Eccles 29156.8 3,035,341 5/1962 Frank et al 72377 3,058,202 10/ 1962 Stalker 72--364 CHARLES W. LANHAM, Primary Examiner.

L. A. LARSON, Assistant Examiner. 

